Urinary acidifiers have been commonly used to acidify the urine of mammals for the purpose of preventing or eliminating urinary crystalloid formation. For example, urinary acidifiers have been widely prescribed by veterinarians to aid in the treatment and prevention of feline urological syndrome (FUS). This condition, characterized by cystitis, urolithiasis, urethritis and urethral blockage, accounts for 10% of the total disease seen in adult male cats. Urethral blockage, moreover, produces extra-renal uremia with elevated blood urea nitrogen (BUN), hyperphosphatemia, hyperkalemia, metabolic acidosis, and death if not treated. Although conclusive data supporting the relationship of urine pH and FUS does not exist, urine acidifiers, nevertheless, are employed to reduce supersaturation of urinary crystalloids and the formation of uroliths. One of the principles suggested for reducing the concentrations of urinary crystalloids is to increase their solubility by reducing urinary pH.
Two of the more popular urinary acidifiers employed at the present time are methionine and ammonium chloride. These compounds have been used to acidify urine in mammals, theoretically by production of sulfuric and hydrochloric acids, respectively. However, both compounds break down and produce ammonia in the body, a compound which is toxic until it is rendered relatively non-toxic by conversion to urea, predominantly in the liver. Excess ammonia is particularly undesirable in mammals with liver and kidney disease. Poorly functioning livers may not efficiently convert ammonia to urea, allowing accumulation of ammonia in the peripheral blood stream, with a resultant hyperammonemia and hepatic encephalopathy. Poorly functioning kidneys may not be able to excrete the excess urea and ammonia caused by administering excess methionine and ammonium chloride, thus contributing to the uremia and hyperammonemia.
Another factor favoring a urinary acidifier which does not release ammonia is the fact that some kidney stones are composed of struvite, a complex compound containing magnesium, ammonium and phosphate. Most commonly used acidifiers such as dl-methionine, ammonium chloride and potassium and sodium phosphates contribute to the body burdens of ammonia and phosphates.
It is an object of the invention, therefore to effectively acidify the urine of mammals such as cats, dogs, pigs, rats, humans and other monogastric mammals, without the usual toxic and undesirable side effects that accompany other commonly employed urinary acidifiers.
Another object of the invention is to effectively prevent or reduce the concentrations of urinary crystalloids in the urine of mammals by treating the mammal with a urinary acidifier that does not yield ammonia as a metabolite.